Australia is a constitutional monarchy located in Oceania whose government is federal parliamentary. It occupies the main continental landmass called Sahul as well as islands in the Pacific, Indian, and Antarctic Oceans. Australia is the sixth largest country by land area and has a population concentrated mainly in coastal cities like Sydney, Melbourne, Brisbane, Perth, and Adelaide as well as the capital of Canberra. The country has been inhabited for over 42,000 years by Australian Aboriginals and was later explored by Europeans starting in the 17th century. Although much of Australia is desert or semi-arid, it has a great diversity of habitats from alpine to tropical forests and is home to many endemic plant and animal species that have adapted to